Power Requirements of Different Impellers

The power required to run a given impeller is dependent on the type of impeller and the geometric configuration of the vessel-impeller combination. Traditionally, the power required by an impeller has been empirically correlated using the dimensionless groups approach. The variables that determine the power required are given by Equation 7A.1  

P=cp p, D, T, g, N, impeller geometric parameters such as blade width, blade angle, thickness, and other geometric details relating impeller and vessel dimensions). The usual dimensionless group approach leads to the following functional relationship  

FIGURE 7A.4 Variation of power number with impeller Reynolds number. 

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